Document Type


Publication Date




Publication Title

Physical Review D








Inspired by recent measurements with the CLAS detector at Jefferson Lab, we perform a self-consistent analysis of world data on the proton structure function g1 in the range 0.17 < Q2 < 30 (GeV/c)2. We compute for the first time low-order moments of g, and study their evolution from small to large values of Q2. The analysis includes the latest data on both the unpolarized inclusive cross sections and the ratio R = σ LT from Jefferson Lab, as well as a new model for the transverse asymmetry A2 in the resonance region. The contributions of both leading and higher twists are extracted, taking into account effects from radiative corrections beyond the next-to-leading order by means of soft-gluon resummation techniques. The leading twist is determined with remarkably good accuracy and is compared with the predictions obtained using various polarized parton distribution sets available in the literature. The contribution of higher twists to the g1 moments is found to be significantly larger than in the case of the unpolarized structure function F2.


© 2005 American Physical Society

"Yes, the author or the author's employer may use all or part of the APS published article, including the APS-prepared version (e.g., the PDF from the online journal) without revision or modification, on the author's or employer's website as long as a fee is not charged. If a fee is charged, then APS permission must be sought. In all cases, the appropriate bibliographic citation and notice of the APS copyright must be included."

Publisher's version available at:

Original Publication Citation

Osipenko, M., Simula, S., Melnitchouk, W., ... Keppel, C., Kuhn, S., & Ricco, G. (2005). Global analysis of data on the proton structure function g₁ and the extraction of its moments. Physical Review D, 71(5), 1-17, Article 054007.


0000-0003-2243-6836 (Kuhn)